> From: André Warnier [mailto:[email protected]]
> Subject: resource file location (was: Logo file location)
>
> The trouble is, it does not really explain what is meant by a "path" in
> that context, and some of the other method descriptions on the same
> page introduce a slight doubt.
Sure it does:
"The path must begin with a "/" and is interpreted as relative to the current
context root.
"This method allows the servlet container to make a resource available to
servlets from any source. Resources can be located on a local or remote file
system, in a database, or in a .war file.
"The servlet container must implement the URL handlers and URLConnection
objects that are necessary to access the resource."
The path parameter is clearly a URL for any resource in the domain of the
context. What the URL actually maps to depends on the configuration of the
webapp and container.
> If it is a real absolute file path on the hosting system
There is no requirement and certainly no guarantee that the host even has a
file system.
> if on that system CATALINA_BASE is "/srv/tomcat/", then supposedly the
> parameter needs to be specified as
> <init-param>
> <param-name>thelogo</param-name>
> <param-value>/srv/tomcat/webapps/myapp/logos/mylogo.jpg</param-value>
> </init-param>
Nope. Read the API spec again: "interpreted as relative to the current context
root." The proper setting is just <param-value>/logos/mylogo.jpg</param-value>.
> That seems to me in flagrant contradiction of the "encapsulation" ideal
> of a webapp and even of Java.
It would be, which is why the spec doesn't do it that way.
> and then used code like
>
> InputStream logo_stream =
> ctx.getResourceAsStream(ctx.getRealPath(ctx.getInitParameter('thelogo')
> ));
Again, getRealPath() should NEVER (well, almost never) be used, since there's
no requirement for it to return anything useful.
> So what is one to do, if one wants not to have to change the content of
> one's war file for each target host, but still allow the webapp to find
> and read the logo ?
You don't - you just have to read the spec correctly, and not ignore the
definition of the parameter.
- Chuck
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